A rotable bucket wheel assembly and a method for refurbishing an associated bucket wheel reclaimer

ABSTRACT

A bucket wheel assembly (40) includes a structural frame (42) that in use forms a structural part of the boom of a bucket wheel reclaimer. The structural frame (42) supports a bucket wheel (44) having a plurality of attached buckets (46); a ring chute (48) and an associated discharge chute (50). The bucket wheel (44) is attached to the middle of shaft (51), which is supported by two bearings (52). The drive unit is attached to the shaft (51) to provide the rotation torque, and the drive unit is also attached to the structure (42). The structural frame (42) couples to a portion of the boom and transfers the assembly load to the boom when the reclaimer is in operation.

TECHNICAL FIELD

A rotable bucket wheel assembly and a method for refurbishing a bucketwheel reclaimer are disclosed.

BACKGROUND ART

The maintenance and repair of a rotable bucket wheel assembly of abucket wheel reclaimer are difficult and expensive exercises. In onemethod, this may involve the disassembly of component parts of therotable bucket wheel assembly such as the bucket wheel itself, drivesystem, drive shaft, bearings, ring chute and discharge chute. Whilethis disassembly occurs, and maintenance is being performed the bucketwheel reclaimer is unable to operate.

To speed up the maintenance process and thereby minimise downtime it hasbeen proposed to construct a rotable bucket wheel assembly as anintegral unit that can be disconnected from a bucket wheel reclaimer andmoved as a unit to a maintenance location. While this is occurring a newor refurbished rotable bucket wheel assembly can be fitted to thereclaimer to enable normal operation.

The above references to the background art do not constitute anadmission that the art forms a part of the common general knowledge of aperson of ordinary skill in the art.

SUMMARY OF THE DISCLOSURE

In one aspect there is disclosed rotable bucket wheel assembly forcoupling to a boom of a bucket wheel reclaimer comprising:

-   -   a bucket wheel;        -   a shaft coupled to the bucketwheel;        -   bearings through which the shaft extends; and        -   a structural frame on which the bucket wheel and shaft are            supported,        -   wherein the structural frame is arranged for demountable            attachment to a boom of a bucket wheel reclaimer.

In one embodiment the structural frame comprises a plurality of couplingpoints to enable coupling to a transfer system to facilitatetransferring the load of the bucket wheel assembly from the boom to thetransfer system whereby the bucket wheel assembly is capable of beingtransported away from the boom by the transfer system.

In one embodiment the coupling points are configured to facilitatecoupling with the transfer system when the transfer system is disposedbeneath the structural frame.

In one embodiment the structural frame is provided with a plurality ofconnecting mechanisms configured to cooperate with complementaryconnecting mechanisms on the boom, wherein when the structural frame isattached to the boom the connecting mechanisms on the frame engage theconnecting mechanisms on the frame.

In one embodiment the connecting mechanisms comprise locating elementsformed on the structural frame and arranged to cooperate with associatedlocating elements on the boom and wherein upon engagement of thelocating elements remaining connecting mechanisms on the structuralframe are in alignment with associated remaining connecting mechanismson the boom.

In one embodiment the locating elements comprise hooks formed on thestructural frame.

In one embodiment the locating elements comprise a plurality of pad eyesconfigured to receive coupling pins.

In one embodiment the rotable bucket assembly comprises a drive systemmounted on the shaft.

In one embodiment the rotable bucket assembly comprises a conveyorpulley rotatably coupled to the structural frame.

In various embodiments the rotable bucket wheel assembly may alsoinclude any one or any combination of two or more of:

-   -   a discharge chute,    -   buckets attached to the bucket wheel,    -   a ring chute,    -   a discharge chute,    -   a plurality of rollers located adjacent the discharge chute, and    -   quick disconnect power and communications cables and water and        lubrication hoses

The structural frame of the assembly forms a part of the boom of thebucket wheel reclaimer. Therefore, embodiments of the disclosed assemblycan facilitate the maintenance of a rotable bucket wheel of a bucketwheel reclaimer by decoupling the structural frame from the remainingpart of the boom and moving it to maintenance location. The bucket wheelassembly can be placed back into operation during the maintenance byattaching the structural frame of a like assembly to the boom.

In a second aspect there is disclosed a boom for a rotable bucket wheelreclaimer comprising:

-   -   a first structural portion having a front end; and    -   a structural frame demountable coupled to the front end of the        first structural portion wherein the structural frame is the        structural frame of a rotable bucket wheel assembly according to        the first aspect.

In a third aspect there is disclosed a method of refurbishing a bucketwheel reclaimer having a boom supporting a rotable bucket wheel assemblythe method comprising:

-   -   forming the boom as a first structural portion and a demountable        structural frame coupled to a front end of the first structural        portion wherein the structural frame is the structural frame of        a rotable bucket wheel assembly in accordance with the first        aspect;    -   uncoupling the structural frame from the front end of the boom;        and    -   moving the bucket wheel assembly as a single unit to a        maintenance location.

In on embodiment, moving the bucket wheel assembly comprisestransferring the load of the bucket wheel assembly to a transfer systemdisposed beneath the structural frame.

In one embodiment the method comprises locating a transfer systembeneath the structural frame and engaging the coupling points of thestructural system with the transfer system wherein the transfer systemcarries the load of the bucket wheel assembly.

In one embodiment the method comprises disconnecting the connectingmechanisms of the structural frame from associated connecting mechanismson the boom when the load of the bucket wheel assembly is transferred tothe transfer system.

In one embodiment transferring the load of the bucket wheel assemblycomprises operating a jack system on the transfer system.

In one embodiment the rotable bucket assembly comprises forming thetransfer system as a transfer frame and a self-propelled modular traileron which the transfer frame is demountable supported.

In one embodiment locating the transfer system comprises driving theself-propelled modular trailer on which the transfer frame isdemountable supported to a position wherein the transfer frame is belowthe structural frame.

In one embodiment engaging the coupling points of the structural systemwith the transfer system comprises one or both of (a) operating theself-propelled modular trailer to lift the transfer frame into contactwith the structural frame; and (b) operating a jack system on thetransfer frame.

In one embodiment the method comprises forming the transfer system as atransfer frame on bogie mounted on a rail system.

In one embodiment locating the transfer system comprises driving thebogie on the rail system to a position wherein the transfer frame isbelow the structural frame.

In a fourth embodiment there is disclosed a transfer system forfacilitating the removal of a bucket wheel assembly from a boom of abucket wheel reclaimer, the transfer system comprising a transport frameconfigured to support the bucket wheel assembly from a location beneaththe bucket wheel assembly, and a jack system coupled with the transportframe and located on a portion of the transfer frame wherein the whenoperated the jack system is able to contact the bucket wheel assemblyand transfer the load of the bucket wheel assembly to the transferframe.

In one embodiment the transfer system comprises: a trailer orself-propelled modular trailer or a rail mounted bogie on which thetransfer frame is supported.

In various embodiments the rotable bucket wheel assembly may alsoinclude any one or any combination of:

-   -   a discharge chute,    -   buckets attached to the bucket wheel,    -   a ring chute,    -   a discharge chute,    -   a plurality of rollers located adjacent the discharge chute    -   a drive unit to rotate the bucket wheel,    -   a conveyor pulley,    -   quick disconnect power and communications cables and water and        lubrication hoses

The structural frame of the assembly forms a part of the boom of thebucket wheel reclaimer. Therefore, embodiments of the disclosed assemblycan facilitate the maintenance of a rotable bucket wheel of a bucketwheel reclaimer by decoupling the structural frame from the remainingpart of the boom and moving it to maintenance location. The bucket wheelassembly can be placed back into operation during the maintenance byattaching the structural frame of a like assembly to the boom.

BRIEF DESCRIPTION OF THE DRAWINGS

Notwithstanding any other forms which may fall within the scope of theapparatus and method as set forth in the Summary, specific embodimentswill now be described, by way of example only, with reference to theaccompanying drawings in which:

FIG. 1 is a photograph of a prior art bucket wheel reclaimer;

FIGS. 2a and 2b are photographs from different angles of a front portionof a boom of a prior art bucket wheel reclaimer showing a rotable bucketwheel;

FIGS. 3a, 3b and 3c are isometric, plan and elevation views respectivelyof a first embodiment of the disclosed rotable bucket wheel assembly;

FIG. 4 is a schematic representation of an embodiment of the disclosedrotable bucket wheel reclaimer which incorporates an embodiment of therotable bucket wheel assembly shown in FIGS. 3a, 3b and 3c

FIG. 5 is a representation of the boom with attached bucket wheelassembly coupled to a support cradle;

FIG. 6 illustrates a transfer system utilised in the method forrefurbishing the bucket wheel assembly being driven toward the boom insupport cradle shown in FIG. 5;

FIG. 7 shows the transfer system located underneath but spaced from thebucket wheel assembly;

FIG. 8 shows a transfer system coupled with the bucket wheel assemblyand elevating the bucket wheel assembly relative to the boom to uncoupleit from the boom, and showing hooks of the structural frame disengagedwith associated pins on the boom;

FIG. 9 shows the transfer system transporting the disconnected bucketwheel assembly away from the boom;

FIG. 10a shows transfer system approaching a maintenance platform;

FIG. 10b shows transfer system in position ready to offload the bucketwheel assembly;

FIG. 10c shows transfer system operated to transfer the load of thebucket wheel assembly to the maintenance platform;

FIG. 10d shows a self-propelled mobile trailer of the transfer systembeing driven out from the maintenance platform;

FIG. 11 depicts one possible arrangement of a maintenance areafacilitating the swap out of a rotable bucket wheel assembly;

FIG. 12 is a schematic representation of a second embodiment of thedisclosed bucket wheel assembly and associated equipment to enableperformance of a second embodiment of a method for refurbishing orswapping out the bucket wheel assembly;

FIG. 13 is a schematic representation of two types of connectionmechanism that may be incorporated in the second embodiment of thedisclosed bucket wheel assembly;

FIG. 14a is a schematic representation of a support cradle that may beincorporated in a method of refurbishing or swapping out a bucket wheelassembly;

FIG. 14b is an enlarged view of a portion of the support cradle shown inFIG. 14 a;

FIG. 14c is a partial section view of a portion of the support cradleshown in FIG. 14 a;

FIG. 15a is a perspective view of a maintenance platform that may beincorporated in the second embodiment of the disclosed method;

FIG. 15b is a schematic representation of a second embodiment of thebucket wheel assembly located within the maintenance platform shown inFIG. 15a and depicting possible degrees of freedom of movementapplicable to the bucket wheel assembly;

FIG. 15c is a further representation of the second embodiment of thebucket wheel assembly in the maintenance platform but depictingadditional degrees of freedom of movement applicable to the bucket wheelassembly;

FIG. 16 is a schematic representation of a transport frame that may beused in the second embodiment of the disclosed method, and incorporatedin a transfer system used to perform the disclosed method;

FIG. 17a is a representation of the transport frame shown in FIG. 16supporting a bucket wheel assembly;

FIG. 17b the schematic representation of a portion of a jack systemincorporated in the transport frame shown in FIG. 17 a;

FIG. 17c the schematic representation of a lift and lock mechanisms ofthe jack system incorporated in the transport frame shown in FIG. 17 a;

FIG. 18 is representation of a third embodiment of the rotable bucketwheel assembly coupled to a boom of a reclaimer showing an approachingtrack mounted transfer system for performing of a third embodiment ofthe disclosed method for refurbishing or swapping out the bucket wheelassembly;

FIG. 19 shows the third embodiment of the disclosed rotable bucket wheelassembly disconnected from the boom and being transported by thetransfer system shown in FIG. 18;

FIG. 20 shows the disconnected rotable bucket wheel assembly andtransfer system of FIG. 19 together with a refurbished or new bucketwheel assembly on a second transfer system approaching the boom;

FIG. 21 shows a portion of the transfer system shown in FIGS. 18-20.

DETAILED DESCRIPTION OF SPECIFIC EMBODIMENT

FIG. 1 shows a prior art bucket wheel reclaimer 10. The reclaimer 10 hasa boom 12 with a rotable bucket wheel 14 supported at a front end. Theboom 12 is pivotally connected at an end opposite the bucket wheel 14 toa body structure 16. A tower 18 extends upwardly from the body structure16 and mechanically supports the front end of the boom 12. The reclaimer10 has rail wheels which run on as associate rail, and a switch room 22.

FIGS. 2a and 2b provide a close-up view of a front end portion of theboom 12 of the bucket wheel reclaimer 10. The bucket wheel 14 isrotatably supported at the front end of the boom 12. The bucket wheel 14is shown with a plurality of attached buckets 24 and a ring chute 26.Material picked up by the buckets 24 as the bucket wheel 14 rotates isdropped by gravity into the ring chute 26 and channeled onto andunderlying conveyor 27.

When the bucket wheel 14 is being maintained or repaired it may bedecoupled from the boom 12 and lifted by a crane onto a transportvehicle, driven to a maintenance location, then lifted again by cranefrom the vehicle onto a purpose-built jig to facilitate maintenanceand/or repair.

FIGS. 3a -4 depict an embodiment of the disclosed rotable bucket wheelassembly 40 (herein after also referred to as “bucket wheel assembly 40”or “assembly 40”) coupled to a boom 12 a of a bucket wheel reclaimer 10a. The bucket wheel assembly 40 includes a structural frame 42 that inuse forms a structural part of the boom of a bucket wheel reclaimer. Thestructural frame 42 supports a bucket wheel 44 having a plurality ofattached buckets 46; a ring chute 48 and associated discharge chute 50.The bucket wheel 44 is attached to the middle of shaft 51, which issupported by two bearings (one shown as item 52, the other being hiddenunder the bucket wheel discharge chute). The drive unit is attached tothe shaft 51 to provide the rotation torque, and the drive unit is alsoattached to the structure 42. The structural frame 42 couples to aportion of the reclaimer boom and transfers the load of the assembly 40to the reclaimer boom when the reclaimer is in operation.

The bucket wheel assembly 40 may also include a plurality of rollers 54in the form of conveyor belt idler support/troughing rollers. Therollers 54 are located adjacent the discharge chute 50. When the bucketwheel assembly 40 is in use, the bucket wheel 44 rotates relative to thering chute 48/discharge chute 50. Material picked up by the buckets 46is held in the buckets by the ring chute 48 and is then dumped bygravity onto the discharge chute 50 onto a conveyor (not shown) thatruns over the rollers 54.

Also supported on the structural frame 42 forward of the rollers 54 is aboom conveyor pulley 56. A reclaimer boom conveyor (not shown), whichruns along the length of the boom, turns about the pulley 54.

The structural frame 42 is provided with a plurality of coupling points58 to facilitate connection to a machine to enable the rotable bucketwheel assembly 40 to be supported and lifted relative to the boom andthen moved away from the reclaimer for example to a repair/maintenancelocation. The coupling points 58 are distributed about the structuralframe 42 to ensure that the load of the rotable bucket wheel assembly 40is substantially balanced when supported and lifted by the crane. Thecoupling points may be in the form of pinned coupling, hooked couplingsor bolted couplings. The coupling points 58 in this embodiment areconfigured to facilitate coupling with a jacking mechanism or machinedisposed beneath the structural frame 42. In this instance the couplingpoints 58 also act as jacking points. Therefore, in this embodimentthere is no need for a crane to lift the structural frame 42 and thebucket wheel assembly 40, but rather a mechanism or machine beneath thebucket wheel assembly 40.

The ability to swap out a bucket wheel assembly 40 without the use of acrane has advantages over know prior art methods. The assembly 40 mayhave a mass in the order of 130 tonnes or more. Therefore, a heavy liftcrane would be required. Such cranes are very expensive to hire and dueto their limited number not always available particularly if anoff-cycle maintenance and repair is required. This is of course not tosay that in other embodiments the coupling points 58 cannot be arrangedto facilitate connection with a crane.

Looking more closely the structural frame 42 has:

-   -   a mounting structure 60 that lies in a generally vertical plane        and facilitates mounting of the bucket wheel assembly 40 to the        remainder of the boom 12 a;    -   a base structure 62 that lies in a generally horizontal plane        and is fixed to the mounting structure 60; and    -   a plurality of diagonally extending braces 64 running from a        upper end of the mounting structure 60 to the base structure 62.

The mounting structure 60 includes a rectangular frame 61 and a numberof connecting mechanisms for connecting the bucket wheel assembly 40 tothe rest of the boom 12 a of a corresponding bucket wheel reclaimer 10a. In this embodiment there are six connecting mechanisms although inother embodiments this number may vary. Also, three different types ofconnecting mechanisms are incorporated. A first type incorporates orcomprises locating elements, in this embodiment in the form of hooks 66,one at each of the upper corners of the rectangular frame 61. The hooks66 are configured to sit on and engage corresponding pins fixed to thedistal end of the boom 12 a.

A second type of connecting mechanism incorporated in this embodiment isa fish plate 68. Three fish plates 68 are provided as part of themounting structure 60. One fish plate 68 is on an upper element of therectangular frame 61 in line with and midway between the hooks 66. Oneof each of the remaining two fish plates 68 are located at the lowercorners of the rectangular frame 61. These two fish plates are inorthogonal plane to the fish plate 68 on the upper element.

A third type of connecting mechanism in this embodiment is a shear key70 (FIG. 3b ). This is in alignment with and midway between the fishplates 68 at the lower corners of the rectangular frame 61.

When coupled to the boom 12 a the hooks 66 carry the vertical load ofthe assembly 40 and shear key 70 transmits lateral forces resulting fromoperation of the reclaimer 10 a. The fish plates 68 are bolted to thefront end of the boom 12 a to demountably fix the assembly 40 to theboom 12 a.

Additionally, during the reattachment of the assembly 40 the hooks 66assists in aligning the bucket wheel assembly 40 and in particular thefish plates 68 to facilitate an operational connection to the boom 12 a

FIGS. 4 to 11 show sequentially an embodiment of the disclosed methodfor replacing/refurbishing a bucket wheel assembly 40.

To start the removal of the bucket wheel assembly 40, the reclaimer 10 ais driven to a location where a front end of the boom 12 a can belowered onto a tie down cradle 72. As shortly explained the removal ofthe bucket wheel assembly 40 also uses a transfer system 71 which inthis embodiment comprises the combination of transport frame 74 and jacksystem which is incorporated in a self-propelled modular trailer (SPMT)76 illustrated in FIGS. 6-10. In general terms the transfer system 71facilitates the removal of a bucket wheel assembly 40 from the boom 12 aof a bucket wheel reclaimer 10 a. The transfer system 71 comprises thetransport frame 74 which is configured to support the bucket wheelassembly 40 from a location beneath the bucket wheel assembly 40, and ajack system coupled with the transport frame 74.

The jack system is operable to enable contact between the transfersystem and the bucket wheel assembly 40. Here the jack system isprovided in or by the SPMT 76 which also is drivable to move or transferthe bucket wheel assembly 40 away from the boom 12 a and the reclaimer10 a. But in other embodiments described later the jack system can beincorporated in the transfer frame 74 itself.

One possible procedure for the removal of the bucket wheel assembly 40will now be described.

As a precursor to decoupling the bucket wheel assembly 40 from the boom12 a the transfer system 71 (i.e. the transport frame 74 loaded on theSPMT 76) is driven close to the tie down cradle 72. The reclaimer 10 ais driven into a location where the boom 12 a can be lowered onto thesupport cradle 72 such as shown in FIGS. 5 and 6. The boom 12 a isluffed down and slewed to a designated slew angle ensuring access by thetransport frame 74 and SPMT 76.

A hold down rope may be slung about the boom connection and secured.Optionally additional jacking cylinders may be installed to jack againstthe boom 12 a to positively arrest the position of the boom 12 a priorto commencing decoupling of the bucket wheel assembly 40.

FIGS. 6, 7 and 8 show sequentially the transfer system 71 being drivenunderneath the bucket wheel assembly 40 to the purposes of removing thebucket wheel assembly 40 from the boom 12 a. FIG. 6 shows the transfersystem 71, constituted by the SPMT 76 on which the transport frame 74 iscarried, being driven in alignment with and toward the bucket wheelassembly 40.

FIG. 7 shows the SPMT 76 and the transport frame 74 (i.e. the transfersystem 71) beneath the bucket wheel assembly 40. The jacking points 58on the structural frame 42 are in alignment with but spaced fromcorresponding seats 78 on the underlying transport frame 74.

With the boom 12 a is supported on the support cradle 72 and arrestedagainst uncontrolled movement:

-   -   electrical, grease, air, water, and comms services are        disconnected;    -   the boom conveyor belt 80 together with associated scrapers and        can be removed (as seen in FIG. 8 which show the roller 56        without the associated belt 80); and    -   the bolts connecting the fish plates 68 to the front end of the        boom 12 a can now be safely removed.

As an aside, the removal of the conveyor belt may be part of a plannedconveyor belt change out.

The bucket wheel assembly 40 can now be jacked upwardly using the jacksystem of the SPMT 76 to lift the hooks 66 above the correspondinglocating pins on the boom 12 a. This is also shown in FIG. 8. The bucketwheel assembly 40 is now totally free of the boom 12 a and its load isfully supported by the transfer system 71.

As shown in FIG. 9 the transfer system 71/SPMT 76 can be driven to amaintenance location. During this process the SPMT 76 can be operated tolower the bucket wheel assembly 40 thereby lowering the centre ofgravity and enhancing safety.

FIG. 10a shows a maintenance platform 82 and associated transport framesupports 84 at a maintenance location. The maintenance platform 82includes stairs and walkways to enable easy access by maintenance staffto the bucket wheel assembly 40. The SPMT 76 is driven so that shoulders86 of the transport frame 74 are in alignment with the supports 84 asshown in FIG. 10b . The SPMT 76 is now lowered so that the shoulders 86engage the supports 84. The load of the transport frame 74 is nowcarried by the supports 84, as depicted in FIG. 10c . The shoulders 86can be bolted to the supports 84 prior to the SPMT 76 being furtherlowered and driven out from under the transport frame 74, as shown inFIG. 10 d.

The SPMT 76 is then driven to pick up a new or refurbished bucket wheelassembly 40′ for installation on the front end of the boom 12 a, asshown in FIG. 11. The new or refurbished bucket wheel assembly 40′ issupported on another transport frame 74 at a location near the supportcradle 72 and elevated for example on supports similar to the supports84 to enable the SPMT 76 to drive beneath the transport frame 74.

The sequence for installation is in essence the reverse of that for theremoval and in summary involves the following steps:

-   -   SPMT 76 is driven to lie beneath the transport frame 74    -   The jack system of the SPMT 76 is operated so that the SPMT 76        contacts and takes the load of the transport frame 74, reforming        the transfer system 71    -   Secure the transport frame 74 to the SPMT 76    -   Drive out and lower the transfer system 71/SPMT 76 down for        travel    -   Drive the SPMT 76 to the reclaimer boom 12 a    -   Position the SPMT 76 with the bucket wheel assembly 40 in front        of the boom 12 a    -   Operate the jack system of the transfer system 71, which is        incorporated in the SPMT 76 to a position where the hooks 66 are        above the corresponding pins on the boom 12 a    -   Manoeuvre the transfer system 71/SPMT 76 to accurately locate        the hooks 66 with the corresponding pins, and the fish plates 68        with a corresponding connection points on the boom 12 a    -   Lower the bucket wheel assembly 40 into the final boarding        position with the shear key 70 engaged    -   Bolt down the bucket wheel assembly 40    -   Operate the jack system to lower the SPMT 76 to clear the bucket        wheel assembly 40 to enable it to be driven out    -   Drive the SPMT 76 away from the reclaimer with the transfer        frame 74    -   Reconnect all disconnected lines and install the new conveyor        belt, the conveyor belt scrapers and control equipment    -   Transport to the transfer frame 74 to a designated storage area        where it is unloaded;    -   Demobilise the SPM to 76.

FIGS. 12-17 c show a second embodiment of the rotable bucket wheelassembly 40 and associated method and equipment for swapping out anassembly 40 for a refurbished or new assembly 40. In describing thisembodiment, the same reference numbers will be used as for the useembodiment to denote the same or substantially same features.

The second embodiment is similar to the first embodiment in that bothhave a structural frame 42 which supports the bucket wheel 44 andconnects onto the boom 12 a; and utilise a transfer system 71 having atransfer frame 74 and SPMT 76 to support and move bucket wheelassemblies 40 to and from the boom 12 a. There are however differencesin the connecting mechanisms operating between the structural frame 42and the boom 12 a as well as differences in how the transfer system 71and in particular the transfer frame 74 engages the structural frame 42.Also, as explained in greater detail below in this embodiment an accessplatform 88 is utilised that supports the transfer frame 74 and providesmultiple degrees of movement for adjusting the position of the bucketwheel assembly 40 which may greatly assist in the reconnection of thebucket wheel assembly 40 to the reclaimer.

The structural fame 42 supports the ring chute 48 and associateddischarge chute 50 which is coupled with the bucket wheel 44, wheelshaft, bearings and drive unit as in the previous embodiment althoughnot individually visible in these figures. The structural frame 42 has amounting structure 60 that includes a rectangular frame 61 and a numberof connecting mechanisms for connecting the bucket wheel assembly 40 tothe boom 12 a.

However instead of three different types and a total of six connectingmechanisms; the structural frame 42 of this embodiment has only twotypes and a total of four connecting mechanisms, as shown in FIG. 13.

The first type of connecting mechanism is in the form of pins 91 thatpass through respective pad eyes formed on the rectangular frame 61 at alocation corresponding to the hooks 66 of the first embodiment. Each padeye locates between corresponding pairs of lugs 95 formed at each uppercorner of the front end of the boom 12 a. Respective pins 91 can then beinserted to couple a pad eye and a corresponding pair of lugs 95.

A second form of connecting mechanism used in this embodiment is a fishplate 68 like that described in relation to the first embodiment.However here only two fish plates are used, one of each lower corner ofthe rectangular frame 61. The fish plates 68 have a large tolerance formisalignment. While the vertical position is restrained by the pins 91,a vertical key is applied in the fish plates 68 to align the connectionin horizontal direction.

FIG. 12 shows the general structure of the bucket wheel assembly 40 aswell as the setup for removing and installing a bucket wheel assembly40. The bucket wheel assembly 40 is attached to a front end of the boom12 a, with the boom 12 a located in its normal storm parking positionand tied onto the support cradle 72. The access platform 88 is adjacentthe support cradle 72. The transfer system 71 is also shown locatedunderneath the bucket wheel assembly 40.

FIGS. 14a-14c show the support cradle 72 used in this embodiment. Thecradle 72 is designed to lock the boom 12 a positively against verticaland horizontal movements and to take the significant uplift forces oncethe bucket wheel assembly 40 has been removed. The cradle 72 has astructure which includes a vertical mainframe 90 that is bracedbackwards.

Two hydraulic tie-down mechanisms 87 with integrated mechanical lockingassemblies are installed on top of the cradle 72. Packer plates 89 areinserted between boom 12 a and cradle upper cross beam 96, once the boom12 a has been lowered. The boom is 12 a pinned to the tie down mechanism87 and pulled against the packer plates 89 with controlled hydraulicpressure, then mechanically locked in position.

For lateral restraint of the boom 12 a, two conventional hand operatedspindle mechanisms 98 are installed each side of the cross beam 96 ofthe cradle 72. Minor boom adjustment is possible within the backlashallowance of the slew gear. Access to the tie down cradle 72 is providedfrom the access platform 88.

FIGS. 15a-15c illustrate an embodiment of the access platform 88. Themain purpose of the access platform 88 is to provide adequate accessaround the bucket wheel assembly 40 during routine maintenanceactivities and for the bucket wheel assembly replacement procedure sothat all necessary work can be executed safely from dedicated walkwayswithout the need of temporary access via EWP or scaffolding. The accessplatform 88 also supports the transport frame 74 loaded with the bucketwheel assembly 40 and accommodates horizontal forces resulting from thealignment of the transport frame, and wind loads.

The access platform 88 has two main horizontal beams 100 on either sideof a central opening providing a parking space for the transfer system71 (SPMT 76 and the transport frame 74). When the transfer system 71 islocated within the central opening the legs of the transport frame 74are supported on the horizontal beams 100. All horizontal totalmovements of the transport frame 74 are actuated and controlled viahydraulic cylinders that on the longitudinal main beams 100 and on across beam 102 at the back of the platform 88. With this arrangement thebucket wheel assembly 40 can be aligned properly and effectively withthe connection points of the boom 12 a from the very course positionattributed to the transfer system 71/SPMT 76 travel, to a preciseposition enabling structural reconnection.

The rotable bucket wheel assembly 40 is adjustable in the horizontalplane by hydraulic cylinders mounted at each corner of the accessplatform 88 and a set of hydraulic cylinders mounted to the back crossbeam 102. The cylinders may be operated from ground level via portablepower packs and with the assistance of spotters. For this purpose, thetransport frame 74 rests on the longitudinal beams 100 and the SPMT 76needs to be removed beforehand. Vertical adjustment of the bucket wheelassembly 40 is achieved via the jack system of the transfer frame 71,which comprises four hydraulic cylinders located under the support pinsbetween bucket wheel assembly 40 and cradle. The cylinders are operatedin a 4/3 configuration which allows tilting about the longitudinal axiswith the two independent back cylinders and tilting about the traverseaxis with the two combined front cylinders. In one non-limiting examplevertical adjustment may be in the order +100 mm under load of theassembly 40.

FIG. 16 shows an example of the transport frame 74 in this embodiment.The frame 74 is formed with legs 104 and shoulders 86. The legs 104enables the frame 74 to be placed on the ground while the shoulders 86are configured to sit on the longitudinal beams 100. In contrast to thefirst embodiment in this embodiment the jack system is provided as apart of the transport frame 74 and is embodied by four vertical lift andlock mechanisms 106. The mechanisms 106 are at locations correspondingthose of the seats 78 in the first embodiment for engaging the jackingpoints 58 of the structural frame 42.

To enable easy access for the assembly 40 replacement, a front crossbeam 108 of the transport frame 74 may have a bolted connection enablingremoval during long term storage (but will need to be reinstalled fortransport). The bucket wheel 44 with buckets 46 attached can be rotatedwhen resting on the transport frame 74.

FIGS. 17a-c show the lift and lock mechanisms 106 and transport frame 74coupled with the assembly 40 and transport frame 74. Each of the lockmechanisms includes a threaded and tapered pin 110 with hole clearanceinside of a corresponding bracket 112. Two nuts 114, 116 are provided tolock (nut 114) and to counter lock (nut 116) the position. The bracket112 provides sufficient clearance to support the pin 110 with ahydraulic jack 118 which is operable to extend and retract the pin 110to adjust the vertical position of the assembly 40. During transport andhorizontal adjustment, the assembly 40 is locked with the four pins 110to the transport frame 74. The pins 110 are pushed into counter sectionsformed in the jacking points 58 of the structural frame 42.

The change out of a rotable bucket wheel assembly 40 involvesrespective: parking; tiedown; removal and installation procedures. Theseare broadly described below.

Parking Procedure

-   -   The reclaimer 10 a is driven to its parking position    -   The storm lock pin is engaged    -   The boom 12 a is slewed to the parking position    -   The boom 12 a is lowered to the primary parking limit    -   The boom 12 a is lowered to the final parking limit    -   The reclaimer 10 a is isolated and washed down

Pre-Tie Down Procedure

Prior to the tie down procedure commencing, the transport frame 74 onthe SPMT 76 (i.e. the transfer system 71) is driven into the centralopening of the platform 88, then lower the SPMT to place the shoulders86 on the longitudinal beams 100.

Tie Down Procedure

The boom 12 a is fully restrained against uplift and lateral movements.This involves in this embodiment the boom 12 a being pulled down to thetie down cradle 72 and secured in vertical and lateral direction. Withreference to FIGS. 14a-14c this can be achieved with the followingprocedure performed at both sides of the support cradle 72simultaneously:

-   -   The boom 12 a is adjusted and locked in lateral direction by use        of the spindle 98 and associated hand-wheel.    -   Packer plates 89 are fitted into a gap between the boom 12 a and        the support for tie down    -   A hydraulic tie down mechanism 87 is connected to the boom 12 a        and mechanically locked against upward movement of the boom    -   The boom 12 a is pulled down to the packer plates 89 by use of        the tie down mechanism    -   The tie down mechanism 87 is locked mechanically    -   The reclaimer luff cylinders (not shown) are bled off so the        full weight of the boom uplift is supported by the cradle.

Rotable Bucket Wheel Assembly Removal Procedure

The rotable bucket wheel assembly 40 is removed as follows:

-   -   Both strands of the conveyor belt are clamped at both sides of        the connecting interface    -   Cut both strands at the connecting interface    -   Disconnect all services (water, lubrication, power and        instrumentation)    -   Align transport frame 74 with the assembly in horizontal plane        using the hydraulics of the platform 88    -   Connect the assembly 40 to the transport frame 74 in vertical        direction with the retractable pins 110 of the jack system    -   Take the load of the assembly 40 with the hydraulic jacks 118        and secure using the nuts 114, 116    -   Remove the bolted connection of the fish plates 68    -   Remove the pin connection 91 assisted by jacking action of the        vertical cylinders    -   Lift the assembly 40 on the transport frame 74 by use of the        SPMT 76    -   Ensure that the assembly 40 is clear of platform 88 and clear of        lugs 95 ready for removal and drive it out    -   Transport the assembly to a temporary storage location and        unload

Rotable Bucket Wheel Assembly Installation Procedure

The installation of a new or refurbished assembly 40 is performed asfollows:

-   -   Drive a transfer system 71 via its corresponding SPMT 76 (which        is a different SPTM 76 to the one carrying the previously        removed assembly 40) with a new/refurbished assembly supported        on a transport frame 74 into the central opening of the platform        88    -   Operate the SPMT 76 to lower the transport frame 74 so that the        shoulders 86 are on the beams 100 of the access platform 88 but        clear of the connection face with the boom 12 a    -   Adjust the location of the frame 74 and assembly 40 to fit to        the connection of the boom    -   Pull the assembly 40 into the connecting position by use of the        hollow plunger cylinders on the transport frame 74 (the push        cylinders push against the platform 88 to fine tune the position        of the transport frame 78 relative to the platform 88)    -   Further adjust as necessary the location of the assembly 40        using the hydraulics of the transport frame 74 to align the pad        eyes of the structural frame between the lugs 95    -   Install the pins 91    -   Readjust if necessary    -   Bolt the fish plates 68 to the boom 12 a    -   Disconnect the assembly form the transport frame 74    -   Connect and recommission all services (water, lubrication, power        and instrumentation)    -   Reverse the tie-down procedure

FIGS. 18-22 show a third embodiment of the rotable bucket wheel assembly40 and associated method and equipment for swapping out an assembly 40for a refurbished or new assembly 40. In describing this embodiment, thesame reference numbers will be used as for the use embodiment to denotethe same or substantially same features.

This embodiment is similar to the second embodiment shown in FIGS. 12-17c in that it uses a transfer system 71 having a transport cradle 74having a jack system comprised of four jacks to engage jacking points onthe structural frame 42 of the rotable bucket wheel assembly 40, anduses a pin connection at the top corners of the structural frame 42adjacent the boom 12 a and bolted connections at the bottom two corners,similar to the pins 91 and fish plate 68 shown in FIG. 13.

With reference to FIGS. 18-20 a substantive difference however lies inthe motive aspect of the transfer system 71 for moving the assembly 40supported on a transport cradle 74 of the transfer system 71 tofacilitate the swapping out the worn assembly 40 for a new orrefurbished assembly 40. In this embodiment the transfer system 71 hasrail mounted bogie system 132 rather than a SPMT 76 as in the first andsecond embodiments. The bogie system 132 supports a structure 130 thatincludes a transport frame 74 as well as an integrated work platform.The bogie system 132 enables the transfer system 71 and associatedtransport frame 74 to move along mutually orthogonal rail tracks 138,142.

The bogie system 132 comprises: a first bogie system enabling movementof the transport frame 74 parallel to and in alignment with the boom 12a along the tracks 138 as shown by double headed arrow 140; and a secondbogie system enabling movement of the transport frame 74 transverse tothe boom 12 a along the tracks 142 as shown by double headed arrow 144.

The bogie systems are equipped with drives to roll in and roll out theassembly 40. Thus, during the shutdown of the reclaimer no additionalmanipulation equipment (such as a trailer, or SPMT) is needed which maycause additional down time as the cradle has to be moved also sideways.

When the transfer system 71 and supported assembly 40 is being movedalong tracks 138 by the first bogie system, the second bogie system isdisengaged. Conversely when the transfer system 71 and supportedassembly 40 is being moved along the tracks 142 by the second bogiesystem, the first bogie system is disengaged. Engagement anddisengagement of the bogie systems is achieved using hydraulics. Thesecond bogie system is disengaged during travel along the tracks 138 andis activated with a hydraulic system once the transverse tracks 142 arereached. Fully engaged, the first bogie system is lifted/retracted andtransverse movement along rail 142 is possible. The complete processmitigates potential risk by not needing any manual work in the vicinityof the cradle

The rail mounted transfer system 71 can achieve minimal down time,accurate pre-adjustment and risk mitigation. The transfer system 71 withthe new assembly 40′ can be located on the rails by trailer or SPMTprior to the shutdown because it is outside of the operation limit ofthe reclaimer. As mentioned previously, no interaction with othertransport equipment during shut down is needed.

If the worn assembly 40 is to be transported to a different location formaintenance work a hydraulic trailer or SPMT 76 (FIG. 20) can be placedunderneath the frame 74 and the complete unit can be lifted andtransported

The procedure for changing out a bucket wheel assembly 40 using thetransfer system 71 will now be described.

1. Positioning of Machine

Prior the shutdown an empty transfer system 71 and a transfer system 71with a refurbished bucket wheel assembly 40 are placed on top of therail system by hydraulic trailer or SPMT in the maintenance area.

The bucket wheel reclaimer 10 a is driven to a maintenance area andslewed to locking position at 32° slew angle.

2. Fixing Machine to ground mounted ballast

The boom 12 a is lowered onto a support cradle (ground mounted ballast),with the boom 12 a luffed to approximately −10°. The horizontaladjustment of the bucket wheel assembly 40 relative to the tracks may bedone by spindles mounted on the storm tower.

The boom 12 a is locked to the ground by either a manual or hydraulicmechanism mounted onto the ground mounted ballast structure. Then adegree of pretension between boom and ground mounted ballast isgenerated by bleeding off the luff cylinders of the reclaimer 10 a. Thepretension is required to have just minimal movement during the changeout process between the boom 12 a and the bucket wheel assembly 40.

3. Bucket wheel head part removal steps.

-   -   Relocate the empty transfer system 71 to a position underneath        the bucket wheel assembly 40 by using the travel drives of the        transfer bogie system and engage the travel drive brakes.    -   Adjust the position of all four hydraulic jacks 118 (two shown        in FIG. 21) of the jack system and extend jacks towards the        structural frame 42 and in particular the coupling points 58. No        pressure is applied when the jacks touch the structural frame 42        but hydraulic lines of the jack system are closed. For        additional safety all jacks may be equipped with locking nuts.    -   Disconnect and unplug all electrical, communication,        lubrication, and water lines between boom 12 a and assembly 40.    -   Install belt pulling equipment in front of the boom 12 a for        worn belt removal.    -   Cut the belt on top side and pull out worn belt.    -   Open all bolts of the fish plate connection at a bottom chord of        the boom 12 a.    -   Open adjustment screws of the two front jacks so that the        movement in boom direction towards the boom end is not locked by        the screw (approximately 20 mm gap).    -   Jack up the two front hydraulic jacks so that a gap (for example        10 mm) is created between the flanges at the bolt connection of        the boom bottom chord.    -   Lock the adjustment screws at the front jacks again and ensure        that all other adjustment screws are locked for avoiding any        movement of a single jack.    -   Jack up the rear jacks to bring the load acting on the pins at        the top chord close to zero.    -   Secure jacks with locking nuts.    -   Retract the pins at the top chord. This may be done by using a        hydraulic push-pulling jack.    -   Lower the bucket wheel assembly 40 down onto fixed stools by        using all four jacks of the jacking system.    -   Insert bolts to fix connection between transfer system 71 and        the bucket wheel assembly 40.    -   Drive the transfer system 71 with the bucket wheel assembly 40        away from the boom 12 a along the tracks 138, 142 to a storage        or maintenance area using the bogie system.

4. New bucket wheel assembly 40 attachment steps

-   -   Drive transfer system 71 with the refurbished bucket wheel        assembly 40 along the tracks 138, 142 towards to boom 12 a.    -   Lift up the bucket wheel assembly 40 by using the jack system        (i.e. the four hydraulic jacks) on top of the transfer frame 74        towards the vertical hard stops on the boom 12 a next to the pin        connection    -   Secure jacks with locking nuts    -   Adjust the bucket wheel assembly 40 in a horizontal plane        towards the hard stop next to the pin connection as required by        using the adjustment screws positioned around the hydraulic        jacks.    -   Insert the pin 91 to connect the pad eyes of the structural        frame 42 to the lugs 95 of the boom 12 a.    -   Operate the jack system to remove the load from the transfer        system 71.    -   Connect the fish plates at the bottom chord of the boom 12 a        with those of the structural frame 42.    -   Drive empty transfer system 71 out to a storage position along        the tracks 140, 100 free to using the bogie system.    -   Connect the cable, water and lubrication connection between boom        12 a and assembly 40.    -   Insert new a new conveyor belt by using belt pulling equipment.    -   Disconnect the boom 12 a from the support structure 72 and        associated the ground mounted ballast.

Embodiments of the disclosed rotable bucket wheel assembly 40 providethe genesis for a new form of boom for a reclaimer. The boom comprisesthe combination of a first structural portion and the structural frame42 of the rotable bucket wheel assembly 40. This combination providesthe substantive structural and operational features of a boom of aconventional reclaimer but of course has the benefit that the bucketwheel assembly 40 which includes the structural frame 42 can bedecoupled together with the remaining components of the rotable bucketwheel assembly 40 as a single unit.

An embodiment of the disclosed method for performing maintenance onand/or repairing a bucket wheel reclaimer includes an initial andprerequisite step of forming the boom of the reclaimer as a firststructural portion and a demountable structural frame coupled to a frontend of the first structural portion. In this method the structural frameincludes the structural frame 42 of the rotable bucket wheel assembly40. The maintenance thereafter involves uncoupling the structural frame42 from the front end of the boom; and lifting the bucket wheel assembly40 by the structural frame 42. This is achieved by attaching thestructural frame 42 to a lifting machine via the lifting points 58. Theuse of cranes can be avoided by lifting the assembly from below, using ajack system. The transfer system 71 can initially support the rotablebucket wheel assembly 40 during decoupling of the structural frame 42from the remainder of the boom. Once the structural frame 42 isdecoupled a vehicle can move or transport the bucket wheel assembly 40which of course includes the structural frame 42 as a single unit to amaintenance location.

In the claims which follow, and in the preceding description, exceptwhere the context requires otherwise due to express language ornecessary implication, the word “comprise” and variations such as“comprises” or “comprising” are used in an inclusive sense, i.e. tospecify the presence of the stated features but not to preclude thepresence or addition of further features in various embodiments of theapparatus and method as disclosed herein.

1. A rotable bucket wheel assembly for coupling to a boom of a bucketwheel reclaimer comprising: a bucket wheel; a shaft coupled to thebucket wheel; bearings through which the shaft extends; and a structuralframe on which the bucket wheel and shaft are supported, wherein thestructural frame is arranged for demountable attachment to an end of aboom of a bucket wheel reclaimer.
 2. The rotable bucket wheel assemblyaccording to claim 1 wherein the structural frame comprises a pluralityof coupling points to enable coupling to a transfer system to facilitatetransferring the load of the bucket wheel assembly from the boom to thetransfer system whereby the bucket wheel assembly is capable of beingtransported away from the boom by the transfer system.
 3. The rotablebucket wheel assembly according to claim 2 wherein the coupling pointsare configured to facilitate coupling with the transfer system when thetransfer system is disposed beneath the structural frame.
 4. The rotablebucket wheel assembly according to claim 1 wherein the structural frameis provided with a plurality of connecting mechanisms configured tocooperate with complementary connecting mechanisms on the boom, whereinwhen the structural frame is attached to the boom the connectingmechanisms on the frame engage the complementary connecting mechanismson the boom.
 5. The rotable bucket wheel assembly according to claim 4wherein the connecting mechanisms comprise locating elements formed onthe structural frame and arranged to cooperate with associated locatingelements on the boom and wherein upon engagement of the locatingelements remaining connecting mechanisms on the structural frame are inalignment with associated remaining connecting mechanisms on the boom.6. The rotable bucket wheel assembly according to claim 5 wherein thelocating elements comprise hooks formed on the structural frame.
 7. Therotable bucket wheel assembly according to claim 5 wherein the locatingelements comprise a plurality of pad eyes configured to receive couplingpins. 8-9. (canceled)
 10. A boom for a rotable bucket wheel reclaimercomprising: a first structural portion having a front end; and astructural frame demountable coupled to the front end of the firststructural portion wherein the structural frame is the structural frameof a rotable bucket wheel assembly according to claim
 1. 11. A method ofrefurbishing a bucket wheel reclaimer having a boom supporting a rotablebucket wheel assembly in accordance with claim 1, the method comprising:forming the boom as a first structural portion and a demountablestructural frame coupled to a front end of the first structural portionwherein the demountable structural frame is the structural frame of arotable bucket wheel assembly; uncoupling the structural frame from thefront end of the boom; and moving the bucket wheel assembly as a singleunit to a maintenance location.
 12. The method according to claim 11wherein moving the bucket wheel assembly comprises transferring the loadof the bucket wheel assembly to a transfer system disposed beneath thestructural frame.
 13. The method according to claim 12 comprisinglocating a transfer system beneath the structural frame and engaging thecoupling points of the structural frame with the transfer system whereinthe transfer system carries the load of the bucket wheel assembly. 14.The method according to claim 13 comprising disconnecting the connectingmechanisms of the structural frame from associated connecting mechanismson the boom when the load of the bucket wheel assembly is transferred tothe transfer system.
 15. The method according to claim 12 whereintransferring the load of the bucket wheel assembly comprises operating ajack system on the transfer system.
 16. The method according to claim 13comprising forming the transfer system as a transfer frame and aself-propelled modular trailer on which the transfer frame isdemountable supported.
 17. The method according to claim 16 whereinlocating the transfer system comprises driving the self-propelledmodular trailer on which the transfer frame is demountable supported toa position wherein the transfer frame is below the structural frame. 18.The method according to claim 16 wherein engaging the coupling points ofthe structural system with the transfer system comprises one or both of(a) operating the self-propelled modular trailer to lift the transferframe into contact with the structural frame; and (b) operating a jacksystem on the transfer frame.
 19. The method according to claim 13comprising forming the transfer system as a transfer frame on bogiemounted on a rail system.
 20. The method according to claim 19 whereinlocating the transfer system comprises driving the bogie on the railsystem to a position wherein the transfer frame is below the structuralframe.
 21. A transfer system when used for removing of a bucket wheelassembly from a boom of a bucket wheel reclaimer wherein the bucketwheel assembly includes a bucket wheel, a shaft coupled to the bucketwheel, bearings through which the shaft extends, and a structural frameon which the bucket wheel and shaft are supported and having a pluralityof coupling points, the transfer system comprising: a transport frameconfigured to support the bucket wheel assembly by engagement with thestructural frame from a location beneath the bucket wheel assembly, anda jack system coupled with the transport frame and located on a portionof the transfer frame wherein the when operated the jack system is ableto contact the coupling points of the structural frame of the bucketwheel assembly and transfer the load of the bucket wheel assembly to thetransfer frame.
 22. The transfer system according to claim 21comprising: a trailer or self-propelled modular trailer or a railmounted bogie on which the transfer frame is supported.